But his departure from Edgeley Park will be viewed as a blow to Sale, whose other international scrum-half - Wales star Dwayne Peel - could also quit when his existing contract expires in May.

Peel, currently sidelined because of a groin injury, has been linked with a move back to Wales or possibly joining an exodus of British players to France.

Wigglesworth said: "I have had nine great years at Sale, but I feel the time is right for a change.

"Everyone can see there is something special happening at Saracens, on and off the field, and I want to be part of it."

Saracens, contenders for this season's Premiership title, currently have three international number nines on their books in South African Neil de Kock, New Zealander Justin Marshall and Fijian Moses Rauluni.

Saracens rugby director Brendan Venter added: "Richard is a top-quality international in the prime of his career, and his eagerness to join Saracens is further evidence this club is going places."